This, I was told, is the top of a trawler, converted to a house. It was brought up the river, craned onto the island (see the crane, below) and is now someone's home.
Here's another from the series of Eel Pie Island drawings. This is an old crane which, despite looking derelict, is still in regular use for lifting boats, engines ... whatever is needed.
Here's another from the Eel Pie Island series. It's of some old machinery, looking hopelessly neglected, but in fact still used. Not sure anyone knows what's in the red drum.